If you been in the gym, you’ve likely heard of high intensity interval training (H.I.I.T.). Whether you’re already using H.I.I.T. or just wondering what it is, here’s what you need to know to make the most of your workouts.

While the name may seem self-explanatory H.I.I.T. is more than just basic interval or circuit training. The signature of H.I.I.T. is alternating extremely difficult workouts with periods of rest. When you’re nearing your maximum limit in an activity your body produces energy anaerobically, but that energy will only sustain you for short periods. True H.I.I.T. requires a 2:1 or 3:1 rest to work ratio. Adequate rest periods are crucial as your body can’t maintain prolonged intensity without recovery.

While H.I.I.T. is of obvious benefit for the athlete looking to improve explosive power and speed it also shows promise for improving overall health and fitness. Cardiorespiratory fitness can be measured as VO2 or the maximum amount of oxygen you can use during exercise. H.I.I.T. has been shown to improve participants’ VO2 as well as blood pressure and insulin sensitivity and contribute to higher calorie burns and weight loss.

There are some safety aspects you should consider before jumping into H.I.I.T. With intense workouts, expecting your body to perform at near max levels quickly, warmups are critical. Proper form is important to avoid injury. Make sure you’re familiar with the correct movements. Make rest days a priority. H.I.I.T. should be limited to one or two workouts a week. Without proper rest between workouts results will fade and injuries will be more likely.

Tags: HIIT, gym, circuit training, maximum limit, anaerobically, energy, recovery, athlete, health fitness, oxygen, intense workout